This invention relates to a sorter with which sheets discharged from an image forming machine such as an electrostatic copying machine or printing machine are sorted out as required and collected, and more particularly to a sorter in which sound noises produced in sorting out such sheets is prevented.
For one example of a sorter in which recording sheets are distributed and received with bin trays which is allowed to move up and down, Japanese Patent unexamined published Application No. 4856/1982 discloses a sorter having a spiral rotary cam mechanism. In this mechanism, trunnions which are circular pins in section are provided at both sides of the upstream end (or sheet receiving end) of each of the bin trays in such a manner as to protrude in a direction of width, and the trunnions thus protruded are moved up and down by cylindrical cams having cylindrical outer walls in which trunnion receiving grooves are spirally formed. In order to allow the trunnion receiving grooves to receive the trunnions successively, the mechanism thus constructed is required to have elastic deflecting means for elastically deflecting the trunnions towards the cams.
Therefore, the resultant mechanism is intricate in construction and is accordingly high in manufacturing cost.
However, the elastic deflecting means may be eliminated by provision of a mechanism for allowing the cams to act directly on the bin trays.
FIG. 1 is an explanatory diagram showing the mechanism. In the mechanism as shown in FIG. 1, bin trays 3-1 and 3-2 include protruded portions which are driven by cams described later, and ring-shaped cams 5-1 and 5-2 are provided for the bin trays in such a manner that they are rotatable about a central axis extended in a predetermined direction and are moved back and forth along the central axis when turned. The ring-shaped cams are designed such that the protrusion length thereof in the front direction along the central axis is gradually increased in a circumferential direction from a predetermined angular position. In moving the bin try upwardly, the cams are rotated to move towards the bin tray; and in moving the bin tray downwardly, they are rotated to move away from the bin tray. Thus, the cams act directly on the lower surfaces of the protruded portions of the bin tray to move the latter upwardly or downwardly.
In the sorter thus constructed, when moving the bin tray upwardly or downwardly, the ring-shaped cams abut against the protruded portions of the bin tray, and then the protruded portions are moved upwardly or downwardly while held by the ring-shaped cams, so that noises are produced.
In a sorter in which recording sheets are distributed and received with a plurality of bin trays moved up and down, as disclosed, for instance, by Japanese Patent Application (OPI) No. 167454/1984, the end portions of the bin trays are inserted respectively in receiving spaces provided in a holder. Accordingly, when the bin tray is moved up and down in the sorter thus constructed, its end portion is vibrated in the receiving space in the holder, thus striking against the upper and lower walls defining the receiving space, to produce noises.